It is projected that by 2030, one in every five Americans will be of retirement age, and this demographic shift is expected to result in more people suffering from dementia. A key feature of the brain is its need for a constant supply of glucose and oxygen to meet the high energy costs of mental activity. This study aims to develop clinically practical, noninvasive imaging methods based on combined positron emission tomography and magnetic resonance imaging to assess brain energy in order to better understand how this critical component of brain health is impacted by aging.

There are now close to six million people in the Unites States living with dementia and this number is only expected to grow as the population continues to age. The current lack of effective treatments for Alzheimer's disease (AD) speaks to the need to better understand the multiple factors that contribute to this complex disease. There is growing evidence that age-related metabolic dysfunction in the brain plays a role in the disease's etiology. This concept has led to treatments aimed at improving brain energy production. Notably, ketogenic dietary supplements have been shown to increase brain ketone metabolism and improve cognitive performance in AD patients. However, the overall benefits to brain metabolism in the AD brain are unknown given the complexity of imaging both oxygen and glucose metabolism in a single session by positron emission tomography (PET). Taking advantage of hybrid PET/MR imaging, this study will combine PET and MRI methods to investigate the effects of a ketogenic supplement on brain oxygen and glucose metabolism in AD patients.

Inclusion Criteria - Healthy Participants: Males and females, Age 21 - 80 years, BMI of 18.5-30

Inclusion Criteria - Alzheimer's Disease Participants: Positive amyloid and tau biomarkers (as noted by PET imaging, cerebrospinal fluid or blood), Mild cognitive impairment or mild-to-moderate dementia, BMI of 18.5-30

Exclusion Criteria: Contraindications to MRI (claustrophobia, metal implants, pacemakers, etc.), Pregnant or breastfeeding women, Neurological disease (healthy participants only), Mental illness, Overt cardio- or neurovascular disease, Recent participation in any procedure(s) involving radioactive agents

Data sets to be shared include imaging data and participant demographics. Data will be made publicly available through the data sharing and archiving platform OpenNeuro.

Data release will follow a 36-month optional embargo to allow time for publication in a peer-reviewed journal.

Data submitted to OpenNeuro are first associated with metadata from the BIDS dataset and with submitter-provided metadata, then indexed for searching. Copies of absorbed content -- from each submitted dataset version -- are subsequently assigned persistent digital object identifiers (DOIs).

Datasets will be made publicly available through OpenNeuro with nominal restrictions using multiple open protocols. Prior to being made public, access to a dataset is controlled through strict authentication policies and an isolated storage backend to further guard against unintended access.

Participants will not know if they have consumed the keytone ester supplement drink or a placebo drink.